#include <stdio.h>
int FindFactor(int n)
{
	if (n == 1)
	{
		return 1;
	}
	return n * FindFactor(n - 1);
}
int main()
{
	int num = 0;
	scanf_s("%d", &num);
	printf("%d", FindFactor(num));
	return 0;
}